Operating income in the quarter reached $405 million, up from $260 million in the year-ago period.

For the full year 2012, Amazon posted a net loss of $39 million, down from a profit of $631 million from the year before. Revenue for the year rose to $61.09 billion from $48.08 billion the year before.

Amazon does not break out figures for product lines such as Kindle or Amazon Web Services. But, CEO and founder Jeff Bezos praised Kindle's performance.

"We're now seeing the transition we've been expecting," Bezos said in a statement. "After five years, e-books is a multibillion dollar category for us and growing fast -- up approximately 70 percent last year."

The earnings report said Kindle Fire HD was the top-selling product across all items available on Amazon worldwide. "At year-end, Kindle Fire HD, Kindle Fire, Kindle Paperwhite and Kindle held the top four spots on the Amazon worldwide best seller charts since launch," the company said.

Analysts were left guessing about the performance of Amazon Web Services, the company's public cloud hosting service.

However, Amazon said in the release that AWS issued 10 price reductions in 2012, for a total of 24 cuts since the service launched in 2006.

The company also said AWS rolled out 159 new services and features in 2012. This is nearly double the services and features launched in 2011.

Tom Szkutak, Amazon's chief financial officer, said during the earnings call, without offering figures, that Amazon made significant expenditures in infrastructure, including with AWS, for "additional capacity."

Doron Kempel says selling hyper-convergence can be challenging for solution providers, but success will come from taking business from competitors that are unprepared or hesitant to embrace the technology.